The Stovebolt Site Forums The Shop Area General Truck Talk Bouncy Fuel Gauge on 54 3100

Not sure where to post this.

The PO had installed a new fuel tank and gauge. The gauge reads fine, but constantly bounces around as the fuel sloshes in the tank. A little of this would be OK, but I think it is excessive. I would like to damp it down somehow. Anyone run into this before? Thanks.

Harry

Was it replaced with a factory original tank and sending unit?

I've had the same problem,in my 52 it's the sending unit it has a dead spot.


Pete

Don, I doubt anything was "factory original." It is a repro, and so is the sending unit, I'm sure. Pete, not sure I follow. To me it looks like over "oversensitivity" problem, rather than a dead spot. Does not do it at all, obviously when it is full. Range of bounce gets greater the emptier the tank is.

A friend suggested that there might be some kind of damper, or maybe some way to restrain the movement of the float lever. Along those lines, on page 23 of the Classic Part catalog, I now see an item called a "gas tank sender unit sock filter." I never heard of this, but maybe that I s exactly what it is used for. Before I order one, has anyone used such a thing?

Harry

I've seen some of the reproduction sending unit that have a plastic float on them. The original either had a cork or brass and the plastic is lighter. I believe that the fluctuation of the gauge is caused by the float being to light and it moves around, thus the gauge is not steady.

I've seen the problem in Hot Rod tanks. Stock tanks usually have some baffles to reduce slosh on cornering, braking, etc.

Some aftermarket tanks are just tanks with, at best, a little baffling around the fuel pickup..

Ok, thanks for the comments. I have decided to pull the float switch and see if I can make the float itself a bit heavier, so it will still float, but not be as "active."

Stay tuned.

Jim hit the nail on the head. The stock tank has baffles. If your hot rod tank does not I don't see a way to stop it. The tank in my '38 is baffled on three sides with the side of the tank making the fourth. There's 1/2" open at the top with only small drainage channels on the bottom.

any electrical engineers out there? it seems to me a capacitor would dampen the gauge.

The sock is for the pick up tube.

Sounds to me like the 'problem' is caused by fuel shifting in the tank. Is this really a problem?

Anyone have foam in the tank? I run a fuel cell which is different than most of you but it has a giant piece of foam in it to correct this issue. Not that it matters as my fuel gauge is not hooked up.

not sure how you'd get a "giant" piece of foam in a stock tank, or prevent it from jamming the sender float .... or be able to still get more than a couple gallons of gas in

Bill

I have no clue I got it from an off road vehicle. I think it's for crash safety also. Works great though.

I thought Jegs had the foam for later installation.

OK, here is a final post. I pulled the sending unit and added a small weight - actually a 1/2 oz. fishing sinker. This did damp the motion somewhat. I declared victory, closed up, and will now leave it alone.

I got a 48 gallon fuel cell out of a trophy truck. Came with the foam and it helps weigh down the rear axle. I hope your fishing weight doesn't detach and clog the line. My 64 c-10 had a bouncy gauge with the tank behind the seat. Never worried about it. If it started I was stoked and I never ran it dry. I fill all my vehicles when they reach a quarter tank. Wish I could get the wife to do that..

Well, I just to make one more post. I kept thinking about it, and decided that what bit needed to damp out the oscillation was not more weight (which affected the accuracy) but more resistance to movement caused by sloshing.

So, thinking outside the box, I found a piece of bronze wool, and attached a golf-ball size piece to the float using a fishing swivel. Well, that did do the trick. Little or no weight, but the bronze wool slowed the movement of the float drastically.

This option cannot affect fuel quality or flow - the pickup is enclosed in a mesh "sock" and feeds the tank-top outlet pipe. Worst case, if anything were to fall off the float, it would go harmlessly to the bottom of the tank.

Case closed.